Package org.dbwiki.data.query.condition

Source Code of org.dbwiki.data.query.condition.PathCondition

/*
    BEGIN LICENSE BLOCK
    Copyright 2010-2011, Heiko Mueller, Sam Lindley, James Cheney and
    University of Edinburgh

    This file is part of Database Wiki.

    Database Wiki is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Database Wiki is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Database Wiki.  If not, see <http://www.gnu.org/licenses/>.
    END LICENSE BLOCK
*/
package org.dbwiki.data.query.condition;

/** Implements a condition with given target path.
*
* @author hmueller
*
*/
import org.dbwiki.data.database.DatabaseElementNode;
import org.dbwiki.data.database.DatabaseGroupNode;

import org.dbwiki.data.query.xpath.XPath;
import org.dbwiki.data.query.xpath.XPathEvaluator;
import org.dbwiki.data.query.xpath.XPathTimestampEvaluator;

import org.dbwiki.data.time.TimeSequence;

public abstract class PathCondition implements Condition, ConditionEvaluator {

  /*
   * Private Variables
   */
 
  private boolean _negated;
  private int _quantifier;
  private XPath _targetPath;
 
 
  /*
   * Constructors
   */
 
  public PathCondition(XPath targetPath, int quantifier, boolean negated) {
 
    _targetPath = targetPath;
    _quantifier = quantifier;
    _negated = negated;
  }

 
  /*
   * Public Methods
   */
 
  public boolean eval(DatabaseElementNode node) {

    EvaluationResult result = new EvaluationResult();
   
    new XPathEvaluator(result).eval((DatabaseGroupNode)node, _targetPath, this);
   
    if (_quantifier == Quantifier.FOR_ALL) {
      if (_negated) {
        return !result.hasAllPositiveEvaluations();
      } else {
        return result.hasAllPositiveEvaluations();
      }
    } else {
      if (_negated) {
        return !result.hasAnyPositiveEvaluation();
      } else {
        return result.hasAnyPositiveEvaluation();
      }
    }
  }
 
  public TimeSequence evalTimestamp(DatabaseElementNode node) {

    TimestampEvaluationResult result = new TimestampEvaluationResult();
   
    new XPathTimestampEvaluator(result).evalTimestamp((DatabaseGroupNode)node, _targetPath, this);
   
    return result.timestamp();
  }
   
  public boolean isNegated() {
   
    return _negated;
  }
 
  public void listConditions(AttributeConditionListing listing) {
    _targetPath.listConditions(listing);
  }

  public XPath targetPath() {
   
    return _targetPath;
  }
 
  public String toString() {
   
    String text = "[";
    if (_negated) {
      text = text + " NOT";
    }
    if (_quantifier == Quantifier.FOR_ALL) {
      text = text + " FOR ALL";
    }
    text = text + " " + _targetPath.toString();
    return text + "]";
  }
}
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